HPV positive neuroendocrine cervical cancer cells are dependent on Myc but not E6/E7 viral oncogenes

Sci Rep. 2017 Apr 5:7:45617. doi: 10.1038/srep45617.

Abstract

Using conditional cell reprogramming, we generated a stable cell culture of an extremely rare and aggressive neuroendocrine cervical cancer. The cultured cells contained HPV-16, formed colonies in soft agar and rapidly produced tumors in immunodeficient mice. The HPV-16 genome was integrated adjacent to the Myc gene, both of which were amplified 40-fold. Analysis of RNA transcripts detected fusion of the HPV/Myc genes, arising from apparent microhomologous recombination. Spectral karyotyping (SKY) and fluorescent-in-situ hybridization (FISH) demonstrated coordinate localization and translocation of the amplified Myc and HPV genes on chromosomes 8 and 21. Similar to the primary tumor, tumor cell cultures expressed very high levels of the Myc protein and, in contrast to all other HPV-positive cervical cancer cell lines, they harbored a gain-of-function mutation in p53 (R273C). Unexpectedly, viral oncogene knockdown had no effect on the growth of the cells, but it did inhibit the proliferation of a conventional HPV-16 positive cervical cancer cell line. Knockdown of Myc, but not the mutant p53, significantly inhibited tumor cell proliferation. On the basis of these data, we propose that the primary driver of transformation in this aggressive cervical cancer is not HPV oncogene expression but rather the overexpression of Myc.

Publication types

  • Research Support, N.I.H., Extramural
  • Research Support, N.I.H., Intramural
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Animals
  • Cell Proliferation*
  • Cell Transformation, Neoplastic*
  • Female
  • Gene Fusion
  • Human papillomavirus 16 / genetics*
  • In Situ Hybridization, Fluorescence
  • Karyotyping
  • Mice
  • Models, Biological
  • Oncogene Proteins, Viral / genetics
  • Oncogene Proteins, Viral / metabolism*
  • Papillomavirus E7 Proteins / genetics
  • Papillomavirus E7 Proteins / metabolism*
  • Proto-Oncogene Proteins c-myc / genetics
  • Proto-Oncogene Proteins c-myc / metabolism*
  • Recombination, Genetic
  • Repressor Proteins / genetics
  • Repressor Proteins / metabolism*
  • Tumor Cells, Cultured
  • Uterine Cervical Neoplasms / physiopathology*

Substances

  • E6 protein, Human papillomavirus type 16
  • Myc protein, mouse
  • Oncogene Proteins, Viral
  • Papillomavirus E7 Proteins
  • Proto-Oncogene Proteins c-myc
  • Repressor Proteins
  • oncogene protein E7, Human papillomavirus type 16